Theoretical models of retinal mosaic formation

Eglen, S. J., Galli-Resta, L., and Reese, B. E. (2003). In: Van Ooyen, A., ed. Modeling Neural Development. Cambridge, MA: MIT Press, pp. 133-150.

Abstract

The spatial distribution of neurons affects the efficiency of neural circuitry. This is particularly evident in the retina, where cells are regularly arranged so that the visual world can be efficiently sampled. In this chapter we outline several developmental mechanisms (cell fate, lateral cell movement, and cell death) by which postmitotic cells become organized into a regular spatial pattern. Here, we focus on two models and review other relevant models. In the first model, the d_min model, cellular positioning is subject only to the constraint that no cell can be closer than some minimal distance to any other cell of the same type. This simple model can account for the distribution of many classes of retinal cells. The second model, the lateral movement model, investigates the suggestion that dendritic interactions control cell positioning. This model shows that lateral movements are sufficient for achieving regularity. We conclude by comparing simulated mosaics produced by these two models and highlight areas of future experimental and theoretical research.